1. Field of the Invention
The technical field of the present invention relates to semiconductor devices including gate driver circuits.
2. Description of the Related Art
An active-matrix display device includes a pixel portion which includes a plurality of pixels provided with elements functioning as switches (e.g., transistors) and a driver circuit which includes a source driver circuit and a gate driver circuit. The source driver circuit outputs a video signal to a pixel provided with an element functioning as a switch when the element is on. The gate driver circuit controls switching of the element functioning as a switch.
The gate driver circuit is provided close to the pixel portion. In the case where the gate driver circuit is provided close to one side of the pixel portion, the region of the pixel portion might lean to one side of the display device. Thus, a display device which has a structure in which a gate driver circuit is separated into right and left in the pixel portion has been proposed.
FIG. 58 illustrates the structure of a display device disclosed in Reference 1. In the display device illustrated in FIG. 58, a first gate driver circuit 5108 and a second gate driver circuit 5110 are symmetrically provided in right and left peripheral regions of a display region.
The first gate driver circuit 5108 is provided in the left peripheral region of the display region. The first gate driver circuit 5108 includes a plurality of shift registers (SRC1 and SRC3 to SRCn+1) whose output terminals are connected to odd-numbered gate lines (GL1 and GL3 to GLn+1). The second gate driver circuit 5110 is provided in the right peripheral region of the display region. The second gate driver circuit 5110 includes a plurality of shift registers (SRC2, SRC4, . . . and SRCn) whose output terminals are connected to even-numbered gate lines (GL2, GL4, . . . and GLn).
The first gate driver circuit 5108 controls an electrical connection between a source driver circuit 5112 and a pixel which is provided in an odd-numbered row in the pixel portion 5102. The second gate driver circuit 5110 controls an electrical connection between the source driver circuit 5112 and a pixel which is provided in an even-numbered row in the pixel portion 5102.